Photoresist defect reduction system and method

ABSTRACT

A system and method for reducing defects in photoresist processing is provided. An embodiment comprises cleaning the photoresist after development using an alkaline environment. The alkaline environment may comprise a neutral solvent and an alkaline developer. The alkaline environment will modify the attraction between residue leftover from development and a surface of the photoresist such that the surfaces repel each other, making the removal of the residue easier. By removing more residue, there will be fewer defects in the photolithographic process.

BACKGROUND

As consumer devices have gotten smaller and smaller in response toconsumer demand, the individual components of these devices havenecessarily decreased in size as well. Semiconductor devices, which makeup a major component of devices such as mobile phones, computer tablets,and the like, have been pressured to become smaller and smaller, with acorresponding pressure on the individual devices (e.g., transistors,resistors, capacitors, etc.) within the semiconductor devices to also bereduced in size.

One enabling technology that is used in the manufacturing processes ofsemiconductor devices is the use of photolithographic materials. Suchmaterials are applied to a surface and then exposed to an energy thathas itself been patterned. Such an exposure modifies the chemical andphysical properties of the exposed regions of the photolithographicmaterial. This modification, along with the lack of modification inregions of the photolithographic material that were not exposed, can beexploited to remove one region without removing the other.

However, as the size of individual devices has decreased, processwindows for photolithographic processing as become tighter and tighter.As such, advances in the field of photolithographic processing have beennecessitated in order to keep up the ability to scale down the devices,and further improvements are needed in order to meet the desired designcriteria such that the march towards smaller and smaller components maybe maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present embodiments, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a photoresist on a semiconductor substrate inaccordance with an embodiment;

FIG. 2 illustrates an exposure of the photoresist in accordance with anembodiment;

FIGS. 3A-3B illustrate a development of the photoresist in accordancewith an embodiment;

FIGS. 4A-4B illustrate a removal of the developer and a residue inaccordance with an embodiment;

FIGS. 5A-5C illustrate an alkaline environment for the removal of theresidue in accordance with an embodiment; and

FIGS. 6A-6B illustrate test results that illustrate the effects of usingan alkaline environment to remove the residue in accordance with anembodiment.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the present embodiments are discussed in detailbelow. It should be appreciated, however, that the present disclosureprovides many applicable inventive concepts that can be embodied in awide variety of specific contexts. The specific embodiments discussedare merely illustrative of specific ways to make and use the disclosedsubject matter, and do not limit the scope of the different embodiments.

Embodiments will be described with respect to a specific context, namelya photoresist cleaning process utilized in the manufacturing ofsemiconductor devices. Other embodiments may also be applied, however,to other cleaning processes of other materials.

With reference now to FIG. 1, there is shown a semiconductor device 100with a substrate 101, active devices 103 on the substrate 101, aninterlayer dielectric (ILD) layer 105 over the active devices 103,metallization layers 107 over the ILD layer 105, a layer to be patterned109 over the ILD layer 105, and a photoresist 111 over the layer to bepatterned 109. The substrate 101 may comprise bulk silicon, doped orundoped, or an active layer of a silicon-on-insulator (SOI) substrate.Generally, an SOI substrate comprises a layer of a semiconductormaterial such as silicon, germanium, silicon germanium, SOI, silicongermanium on insulator (SGOI), or combinations thereof. Other substratesthat may be used include multi-layered substrates, gradient substrates,or hybrid orientation substrates.

The active devices 103 are represented in FIG. 1 as a single transistor.However, as one of skill in the art will recognize, a wide variety ofactive devices such as capacitors, resistors, inductors and the like maybe used to generate the desired structural and functional requirementsof the design for the semiconductor device 100. The active devices 103may be formed using any suitable methods either within or else on thesurface of the substrate 101.

The ILD layer 105 may comprise a material such as boron phosphoroussilicate glass (BPSG), although any suitable dielectrics may be used foreither layer. The ILD layer 105 may be formed using a process such asPECVD, although other processes, such as LPCVD, may alternatively beused. The ILD layer 105 may be formed to a thickness of between about100 Å and about 3,000 Å.

The metallization layers 107 are formed over the substrate 101, theactive devices 103, and the ILD layer 105 and are designed to connectthe various active devices 103 to form functional circuitry. Whileillustrated in FIG. 1 as a single layer, the metallization layers 107are formed of alternating layers of dielectric and conductive materialand may be formed through any suitable process (such as deposition,damascene, dual damascene, etc.). In an embodiment there may be fourlayers of metallization separated from the substrate 101 by the ILDlayer 105, but the precise number of metallization layers 107 isdependent upon the design of the semiconductor device 100.

A layer to be patterned 109 or otherwise processed using the photoresist111 is formed over the metallization layers 107. The layer to bepatterned 109 may be an upper layer of the metallization layers 107 orelse may be a dielectric layer (such as a passivation layer) formed overthe metallization layers 107. In an embodiment in which the layer to bepatterned 109 is a metallization layer, the layer to be patterned 109may be formed of a conductive material using processes similar to theprocesses used for the metallization layers (e.g., damascene, dualdamascene, deposition, etc.). Alternatively, if the layer to bepatterned 109 is a dielectric layer the layer to be patterned 109 may beformed of a dielectric material using such processes as deposition,oxidation, or the like.

However, as one of ordinary skill in the art will recognize, whilematerials, processes, and other details are described in theembodiments, these details are merely intended to be illustrative ofembodiments, and are not intended to be limiting in any fashion. Rather,any suitable layer, made of any suitable material, by any suitableprocess, and any suitable thickness, may alternatively be used. All suchlayers are fully intended to be included within the scope of theembodiments.

The photoresist 111 is applied to the layer to be patterned 109. In anembodiment the photoresist 111 includes a polymer resin along with oneor more photoactive compounds (PACs) in a solvent. In an embodiment thepolymer resin may comprise a hydrocarbon structure (such as a alicyclichydrocarbon structure) that contains one or more groups that willdecompose (e.g., acid leaving groups) or otherwise react when mixed withacids, bases, or free radicals generated by the PACs (as furtherdescribed below). In an embodiment the hydrocarbon structure comprises arepeating unit that forms a skeletal backbone of the polymer resin. Thisrepeating unit may include acrylic esters, methacrylic esters, crotonicesters, vinyl esters, maleic diesters, fumaric diesters, itaconicdiesters, (meth)acrylonitrile, (meth)acrylamides, styrenes, vinylethers, combinations of these, or the like.

Specific structures which may be utilized for the repeating unit of thehydrocarbon structure include methyl acrylate, ethyl acrylate, n-propylacrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate,tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate,acetoxyethyl acrylate, phenyl acrylate, 2-hydroxyethyl acrylate,2-methoxyethyl acrylate, 2-ethoxyethyl acrylate,2-(2-methoxyethoxy)ethyl acrylate, cyclohexyl acrylate, benzyl acrylate,2-alkyl-2-adamantyl (meth)acrylate or dialkyl(1-adamantyl)methyl(meth)acrylate, methyl methacrylate, ethyl methacrylate, n-propylmethacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, tert-butyl methacrylate, n-hexyl methacrylate,2-ethylhexyl methacrylate, acetoxyethyl methacrylate, phenylmethacrylate, 2-hydroxyethyl methacrylate, 2-methoxyethyl methacrylate,2-ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethyl methacrylate,cyclohexyl methacrylate, benzyl methacrylate, 3-chloro-2-hydroxypropylmethacrylate, 3-acetoxy-2-hydroxypropyl methacrylate,3-chloroacetoxy-2-hydroxypropyl methacrylate, butyl crotonate, hexylcrotonate and the like. Examples of the vinyl esters include vinylacetate, vinyl propionate, vinyl butylate, vinyl methoxyacetate, vinylbenzoate, dimethyl maleate, diethyl maleate, dibutyl maleate, dimethylfumarate, diethyl fumarate, dibutyl fumarate, dimethyl itaconate,diethyl itaconate, dibutyl itaconate, acrylamide, methyl acrylamide,ethyl acrylamide, propyl acrylamide, n-butyl acrylamide, tert-butylacrylamide, cyclohexyl acrylamide, 2-methoxyethyl acrylamide, dimethylacrylamide, diethyl acrylamide, phenyl acrylamide, benzyl acrylamide,methacrylamide, methyl methacrylamide, ethyl methacrylamide, propylmethacrylamide, n-butyl methacrylamide, tert-butyl methacrylamide,cyclohexyl methacrylamide, 2-methoxyethyl methacrylamide, dimethylmethacrylamide, diethyl methacrylamide, phenyl methacrylamide, benzylmethacrylamide, methyl vinyl ether, butyl vinyl ether, hexyl vinylether, methoxyethyl vinyl ether, dimethylaminoethyl vinyl ether and thelike. Examples of the styrenes include styrene, methyl styrene, dimethylstyrene, trimethyl styrene, ethyl styrene, isopropyl styrene, butylstyrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichloro styrene, bromo styrene, vinyl methyl benzoate,α-methyl styrene, maleimide, vinylpyridine, vinylpyrrolidone,vinylcarbazole, combinations of these, or the like.

In an embodiment the repeating unit of the hydrocarbon structure mayalso have either a monocyclic or a polycyclic hydrocarbon structuresubstituted into it, or else the monocyclic or polycyclic hydrocarbonstructure may be the repeating unit, in order to form an alicyclichydrocarbon structure. Specific examples of monocyclic structures thatmay be used include bicycloalkane, tricycloalkane, tetracycloalkane,cyclopentane, cyclohexane, or the like. Specific examples of polycyclicstructures that may be used include cycloalkane, adamantine, adamantine,norbornane, isobornane, tricyclodecane, tetracycododecane, or the like.

The group which will decompose, otherwise known as a leaving group or,in an embodiment in which the PAC is a photoacid generator, an acidleaving group is attached to the hydrocarbon structure so that it willreact with the acids/bases/free radicals generated by the PACs duringexposure. In an embodiment the group which will decompose may be acarboxylic acid group, a fluorinated alcohol group, a phenolic alcoholgroup, a sulfonic group, a sulfonamide group, a sulfonylimido group, an(alkylsulfonyl)(alkylcarbonyl)methylene group, an(alkylsulfonyl)(alkyl-carbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsylfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl methylene group, a tris(alkylsulfonyl)methylenegroup, combinations of these, or the like. Specific groups that may beutilized for the fluorinated alcohol group include fluorinatedhydroxyalkyl groups, such as a hexafluoroisopropanol group. Specificgroups that may be utilized for the carboxylic acid group includeacrylic acid groups, methacrylic acid groups, or the like.

In an embodiment the polymer resin may also comprise other groupsattached to the hydrocarbon structure that help to improve a variety ofproperties of the polymerizable resin. For example, inclusion of alactone group to the hydrocarbon structure assists to reduce the amountof line edge roughness after the photoresist 111 has been developed,thereby helping to reduce the number of defects that occur duringdevelopment. In an embodiment the lactone groups may include ringshaving five to seven members, although any suitable lactone structuremay alternatively be used for the lactone group.

The polymer resin may also comprise groups that can assist in increasingthe adhesiveness of the photoresist 111 to underlying structures (e.g.,the layer to be patterned 109). In an embodiment polar groups may beused to help increase the adhesiveness, and polar groups that may beused in this embodiment include hydroxyl groups, cyano groups, or thelike, although any suitable polar group may alternatively be utilized.

Optionally, the polymer resin may further comprise one or more alicyclichydrocarbon structures that do not also contain a group which willdecompose. In an embodiment the hydrocarbon structure that does notcontain a group which will decompose may include structures such as1-adamantyl(meth)acrylate, tricyclodecanyl (meth)acrylate, cyclohexayl(meth)acrylate, combinations of these, or the like.

Additionally, the photoresist 111 also comprises one or more PACs. ThePACs may be photoactive components such as photoacid generators,photobase generators, free-radical generators, or the like, and the PACsmay be positive-acting or negative-acting. In an embodiment in which thePACs are a photoacid generator, the PACs may comprise halogenatedtriazines, onium salts, diazonium salts, aromatic diazonium salts,phosphonium salts, sulfonium salts, iodonium salts, imide sulfonate,oxime sulfonate, disulfone, o-nitrobenzylsulfonate, sulfonated esters,halogenerated sulfonyloxy dicarboximides, diazodisulfones,α-cyanooxyamine-sulfonates, imidesulfonates, ketodiazosulfones,sulfonyldiazoesters, 1,2-di(arylsulfonyl)hydrazines, nitrobenzyl esters,and the s-triazine derivatives, suitable combinations of these, and thelike.

Specific examples of photoacid generators that may be used includeα.-(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarbo-ximide(MDT), N-hydroxy-naphthalimide (DDSN), benzoin tosylate,t-butylphenyl-α-(p-toluenesulfonyloxy)-acetate andt-butyl-α-(p-toluenesulfonyloxy)-acetate, triarylsulfonium anddiaryliodonium hexafluoroantimonates, hexafluoroarsenates,trifluoromethanesulfonates, iodonium perfluorooctanesulfonate,N-camphorsulfonyloxynaphthalimide,N-pentafluorophenylsulfonyloxynaphthalimide, ionic iodonium sulfonatessuch as diaryl iodonium (alkyl or aryl)sulfonate andbis-(di-t-butylphenyl)iodonium camphanylsulfonate,perfluoroalkanesulfonates such as perfluoropentanesulfonate,perfluorooctanesulfonate, perfluoromethanesulfonate, aryl (e.g., phenylor benzyl)triflates such as triphenylsulfonium triflate orbis-(t-butylphenyl)iodonium triflate; pyrogallol derivatives (e.g.,trimesylate of pyrogallol), trifluoromethanesulfonate esters ofhydroxyimides, α,α′-bis-sulfonyl-diazomethanes, sulfonate esters ofnitro-substituted benzyl alcohols, naphthoquinone-4-diazides, alkyldisulfones, and the like.

In an embodiment in which the PACs are a free-radical generator, thePACs may comprise n-phenylglycine, aromatic ketones such asbenzophenone, N,N-tetramethyl-4,4′-diaminobenzophenone,N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzo-phenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzo-phenone,p,p′-bis(diethylamino)-benzophenone, anthraquinone,2-ethylanthraquinone, naphthaquinone and phenanthraquinone, benzoinssuch as benzoin, benzoinmethylether, benzomethylether,benzoinisopropylether, benzoin-n-butylether, benzoin-phenylether,methylbenzoin and ethybenzoin, benzyl derivatives such as dibenzyl,benzyldiphenyldisulfide and benzyldimethylketal, acridine derivativessuch as 9-phenylacridine and 1,7-bis(9-acridinyl)heptane, thioxanthonessuch as 2-chlorothioxanthone, 2-methylthioxanthone,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone and2-isopropylthioxanthone, acetophenones such as 1,1-dichloroacetophenone,p-t-butyldichloro-acetophenone, 2,2-diethoxyacetophenone,2,2-dimethoxy-2-phenylacetophenone, and2,2-dichloro-4-phenoxyacetophenone, 2,4,5-triarylimidazole dimers suchas 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di-(m-methoxyphenyl imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)—5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer and2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimmer, suitablecombinations of these, or the like.

In an embodiment in which the PACs are a photobase generator, the PACsmay comprise quaternary ammonium dithiocarbamates, a aminoketones,oxime-urethane containing molecules such as dibenzophenoneoximehexamethylene diurethan, ammonium tetraorganylborate salts, andN-(2-nitrobenzyloxycarbonyl)cyclic amines, suitable combinations ofthese, or the like. However, as one of ordinary skill in the art willrecognize, the chemical compounds listed herein are merely intended asillustrated examples of the PACs and are not intended to limit theembodiments to only those PACs specifically described. Rather, anysuitable PAC may alternatively be utilized, and all such PACs are fullyintended to be included within the scope of the present embodiments.

The individual components of the photoresist 111 may be placed into asolvent in order to aid in the mixing and placement of the photoresist111. To aid in the mixing and placement of the photoresist 111, thesolvent is chosen at least in part based upon the materials chosen forthe polymer resin as well as the PACs. In particular, the solvent ischosen such that the polymer resin and the PACs can be evenly dissolvedinto the solvent and dispensed upon the layer to be patterned 109.

In an embodiment the solvent may be an organic solvent, and may compriseany suitable solvent such as ketones, alcohols, polyalcohols, ethers,glycol ethers, cyclic ethers, aromatic hydrocarbons, esters,propionates, lactates, lactic esters, alkylene glycol monoalkyl ethers,alkyl lactates, alkyl alkoxypropionates, cyclic lactones, monoketonecompounds that contain a ring, alkylene carbonates, alkyl alkoxyacetate,alkyl pyruvates, ethylene glycol alkyl ether acetates, diethyleneglycols, propylene glycol alkyl ether acetates, alkylene glycol alkylether esters, alkylene glycol monoalkyl esters, or the like.

Specific examples of materials that may be used as the solvent for thephotoresist 111 include, acetone, methanol, ethanol, toluene, xylene,4-hydroxy-4-methyl-2-pentatone, tetrahydrofuran, methyl ethyl ketone,cyclohexanone, methyl isoamyl ketone, 2-heptanone, ethylene glycol,ethylene glycol monoacetate, ethylene glycol dimethyl ether, ethyleneglycol dimethyl ether, ethylene glycol methylethyl ether, ethyleneglycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolveacetate, diethylene glycol, diethylene glycol monoacetate, diethyleneglycol monomethyl ether, diethylene glycol diethyl ether, diethyleneglycol dimethyl ether, diethylene glycol ethylmethyl ether, diethyleneglycol monoethyl ether, diethylene glycol monobutyl ether, ethyl2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate,methyl 2-hydroxy-2-methylbutanate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, methyl 3-ethoxypropionate, ethyl3-ethoxypropionate, ethyl acetate, butyl acetate, methyl lactate andethyl lactate, propylene glycol, propylene glycol monoacetate, propyleneglycol monoethyl ether acetate, propylene glycol monomethyl etheracetate, propylene glycol monopropyl methyl ether acetate, propyleneglycol monobutyl ether acetate, propylene glycol monobutyl etheracetate, propylene glycol monomethyl ether propionate, propylene glycolmonoethyl ether propionate, propylene glycol methyl ether adcetate,proplylene glycol ethyl ether acetate, ethylene glycol monomethyl etheracetate, ethylene glycol monoethyl ether acetate, propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmonopropyl ether, propylene glycol monobutyl ether, ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, propyl lactate, andbutyl lactate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate,methyl 3-ethoxypropionate, and ethyl 3-methoxypropionate,β-propiolactone, β-butyrolactone, γ-butyrolactone,α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone,γ-caprolactone, γ-octanoic lactone, α-hydroxy-γ-butyrolactone,2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone,4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone,2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone,3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone,2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone,2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone,3-decanone, 4-decanone, 5-hexene-2-one, 3-pentene-2-one, cyclopentanone,2-methylcyclopentanone, 3-methylcyclopentanone,2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone,cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone,4-ethylcyclohexanone, 2,2-dimethylcyclohexanone,2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone,2-methylcycloheptanone, 3-methylcycloheptanone, pylene carbonate,vinylene carbonate, ethylene carbonate, and butylene carbonate,acetate-2-methoxyethyl, acetate-2-ethoxyethyl,acetate-2-(2-ethoxyethoxy)ethyl, acetate-3-methoxy-3-methylbutyl,acetate-1-methoxy-2-propyl, dipropylene glycol, monomethylether,monoethylether, monopropylether, monobutylehter, monophenylether,dipropylene glycol monoacetate, dioxane, methyl acetate, ethyl acetate,butyl acetate, methyl puruvate, ethyl puruvate, propyl pyruvate, methylmethoxypropionate, ethyl ethoxypropionate, n-methylpyrrolidone (NMP),2-methoxyethyl ether (diglyme), ethylene glycol monom-ethyl ether,propylene glycol monomethyl ether; methyl proponiate, ethyl proponiateand ethyl ethoxy proponiate, methylethyl ketone, cyclohexanone,2-heptanone, carbon dioxide, cyclopentatone, cyclohexanone, ethyl3-ethocypropionate, ethyl lactate, propylene glycol methyl ether acetate(PGMEA), methylene cellosolve, butyle acetate, and 2-ethoxyethanol,N-methylformamide, N,N-dimethylformamide, N-methylformanilide,N-methylacetamide, N,N-dimethylacetamide, N-methylpyrrolidone,dimethylsulfoxide, benzyl ethyl ether, dihexyl ether, acetonylacetone,isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzylalcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethylmaleate, γ-butyrolactone, ethylene carbonate, propylene carbonate,phenyl cellosolve acetate, or the like.

However, as one of ordinary skill in the art will recognize, thematerials listed and described above as examples of materials that maybe utilized for the solvent component of the photoresist 111 are merelyillustrative and are not intended to limit the embodiments. Rather, anysuitable material that may dissolve the polymer resin and the PACs mayalternatively be utilized to help mix and apply the photoresist 111. Allsuch materials are fully intended to be included within the scope of theembodiments.

Additionally, while individual ones of the above described materials maybe used as the solvent for the photoresist 111, in alternativeembodiments more than one of the above described materials may beutilized. For example, the solvent may comprise a combination mixture oftwo or more of the materials described. All such combinations are fullyintended to be included within the scope of the embodiments.

Optionally, a cross-linking agent may also be added to the photoresist111. The cross-linking agent reacts with the polymer resin within thephotoresist 111 after exposure, assisting in increasing thecross-linking density of the photoresist, which helps to improve theresist pattern and resistance to dry etching. In an embodiment thecross-linking agent may be an melamine based agent, a urea based agent,ethylene urea based agent, propylene urea based agent, glycoluril basedagent, an aliphatic cyclic hydrocarbon having a hydroxyl group, ahydroxyalkyl group, or a combination of these, oxygen containingderivatives of the aliphatic cyclic hydrocarbon, glycoluril compounds,etherified amino resins, combinations of these, or the like.

Specific examples of materials that may be utilized as a cross-linkingagent include melamine, acetoguanamine, benzoguanamine, urea, ethyleneurea, or glycoluril with formaldehyde, glycoluril with a combination offormaldehyde and a lower alcohol, hexamethoxymethylmelamine,bismethoxymethylurea, bismethoxymethylbismethoxyethylene urea,tetramethoxymethylglycoluril, and tetrabutoxymethylglycoluril, mono-,di-, tri-, or tetra-hydroxymethylated glycoluril, mono-, di-, tri-,and/or tetra-methoxymethylated glycoluril, mono-, di-, tri-, and/ortetra-ethoxymethylated glycoluril, mono-, di-, tri-, and/ortetra-propoxymethylated glycoluril, and mono-, di-, tri-, and/ortetra-butoxymethylated glycoluril,2,3-dihydroxy-5-hydroxymethylnorbornane,2-hydroy-5,6-bis(hydroxymethyl)norbornane, cyclohexanedimethanol,3,4,8(or 9)-trihydroxytricyclodecane, 2-methyl-2-adamantanol,1,4-dioxane-2,3-diol and 1,3,5-trihydroxycyclohexane, tetramethoxymethylglycoluril, methylpropyltetramethoxymethyl glycoluril, andmethylphenyltetramethoxymethylglycoluril,2,6-bis(hydroxymethyl)p-cresol, N-methoxymethyl- orN-butoxymethyl-melamine. Additionally, compounds obtained by reactingformaldehyde, or formaldehyde and lower alcohols with aminogroup-containing compounds, such as melamine, acetoguanamine,benzoguanamine, urea, ethylene urea and glycoluril, and substituting thehydrogen atoms of the amino group with hydroxymethyl group or loweralkoxymethyl group, examples being hexamethoxymethylmelamine,bismethoxymethyl urea, bismethoxymethylbismethoxyethylene urea,tetramethoxymethyl glycoluril and tetrabutoxymethyl glycoluril,copolymers of 3-chloro-2-hydroxypropyl methacrylate and methacrylicacid, copolymers of 3-chloro-2-hydroxypropyl methacrylate and cyclohexylmethacrylate and methacrylic acid, copolymers of3-chloro-2-hydroxypropyl methacrylate and benzyl methacrylate andmethacrylic acid, bisphenol A-di(3-chloro-2-hydroxypropyl)ether,poly(3-chloro-2-hydroxypro-pyl)ether of a phenol novolak resin,pentaerythritol tetra(3-chloro-2-hydroxypropyl)ether, trimethylolmethanetri(3-chloro-2-hydroxypropyl)ether phenol, bisphenolA-di(3-acetoxy-2-hydroxypropyl)ether,poly(3-acetoxy-2-hydroxypropyl)ethe-r of a phenol novolak resin,pentaerythritol tetra(3-acetoxy-2-hydroxyprop-yl)ether, pentaerythritolpoly(3-chloroacetoxy-2-hydroxypropyl)ether, trimethylolmethanetri(3-acetoxy-2-hydroxypropyl)ether, combinations of these, or the like.

In addition to the polymer resins, the PACs, the solvents, and thecross-linking agents, the photoresist 111 may also include a number ofother additives that will assist the photoresist 111 obtain the highestresolution. For example, the photoresist 111 may also includesurfactants in order to help improve the ability of the photoresist 111to coat the surface on which it is applied. In an embodiment thesurfactants may include nonionic surfactants, polymers havingfluorinated aliphatic groups, surfactants that contain at least onefluorine atom and/or at least one silicon atom, polyoxyethylene alkylethers, polyoxyethylene alkyl aryl ethers,polyoxyethylene-polyoxypropylene block copolymers, sorbitan fatty acidesters, polyoxyethylene sorbitan fatty acid esters.

Specific examples of materials that may be used as surfactants includepolyoxyethylene lauryl ether, polyoxyethylene stearyl ether,polyoxyethylene cetyl ether, polyoxyethylene oleyl ether,polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether,sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate,sorbitan monooleate, sorbitan trioleate, sorbitan tristearate,polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate, polyoxyethylene sorbitan tristearate, polyethyleneglycol distearate, polyethylene glycol dilaurate, polyethylene glycol,polypropylene glycol, polyoxyethylenestearyl ether and polyoxyethylenecetyl ether; fluorine containing cationic surfactants, fluorinecontaining nonionic surfactants, fluorine containing anionicsurfactants, cationic surfactants and anionic surfactants, polyethyleneglycol, polypropylene glycol, polyoxyethylene cetyl ether, combinationsof these, or the like.

Another additive that may be added to the photoresist 111 is a quencher,which may be utilized to inhibit diffusion of the generatedacids/bases/free radicals within the photoresist, which helps the resistpattern configuration as well as to improve the stability of thephotoresist 111 over time. In an embodiment the quencher is an aminesuch as a second lower aliphatic amine, a tertiary lower aliphaticamine, or the like. Specific examples of amines that may be used includetrimethylamine, diethylamine, triethylamine, di-n-propylamine,tri-n-propylamine, tripentylamine, diethanolamine, and triethanolamine,alkanolamine, combinations of these, or the like.

Alternatively, an organic acid may be utilized as the quencher. Specificembodiments of organic acids that may be utilized include malonic acid,citric acid, malic acid, succinic acid, benzoic acid, salicylic acid,phosphorous oxo acid and its derivatives such as phosphoric acid andderivatives thereof such as its esters, such as phosphoric acid,phosphoric acid di-n-butyl ester and phosphoric acid diphenyl ester;phosphonic acid and derivatives thereof such as its ester, such asphosphonic acid, phosphonic acid dimethyl ester, phosphonic aciddi-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester,and phosphonic acid dibenzyl ester; and phosphinic acid and derivativesthereof such as its esters, including phosphinic acid andphenylphosphinic acid.

Another additive that may be added to the photoresist 111 is astabilizer, which assists in preventing undesired diffusion of the acidsgenerated during exposure of the photoresist 111. In an embodiment thestabilizer may include nitrogenous compounds such as aliphatic primary,secondary, and tertiary amines, cyclic amines such as piperidines,pyrrolidines, morpholines, aromatic heterocycles such as pyridines,pyrimidines, purines, imines such as diazabicycloundecene, guanidines,imides, amides, and others. Alternatively, ammonium salts may also beused for the stabilizer, including ammonium, primary, secondary,tertiary, and quaternary alkyl- and arylammonium salts of alkoxidesincluding hydroxide, phenolates, carboxylates, aryl and alkylsulfonates, sulfonamides, and others. Other cationic nitrogenouscompounds including pyridinium salts and salts of other heterocyclicnitrogenous compounds with anions such as alkoxides including hydroxide,phenolates, carboxylates, aryl and alkyl sulfonates, sulfonamides, andthe like may also be employed.

Yet another additive that may be added to the photoresist 111 may be adissolution inhibitor in order to help control dissolution of thephotoresist 111 during development. In an embodiment bile-salt estersmay be utilized as the dissolution inhibitor. Specific examples ofmaterials that may be utilized include cholic acid (IV), deoxycholicacid (V), lithocholic acid (VI), t-butyl deoxycholate (VII), t-butyllithocholate (VIII), and t-butyl-3-α-acetyl lithocholate (IX).

Another additive that may be added to the photoresist 111 may be aplasticizer. Plasticizers may be used to reduce delamination andcracking between the photoresist 111 and underlying layers (e.g., thelayer to be patterned 109) and may comprise monomeric, oligomeric, andpolymeric plasticizers such as oligo-anpolyethyleneglycol ethers,cycloaliphatic esters, and non-acid reactive steroidally-derivedmaterials. Specific examples of materials that may be used for theplasticizer include dioctyl phthalate, didodecyl phthalate, triethyleneglycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate,dioctyl adipate, dibutyl sebacate, triacetyl glycerine and the like.

Yet another additive that may be added include a coloring agent, whichhelps observers examine the photoresist 111 and find any defects thatmay need to be remedied prior to further processing. In an embodimentthe coloring agent may be either a triarylmethane dye or, alternatively,may be a fine particle organic pigment. Specific examples of materialsthat may be used as coloring agents include crystal violet, methylviolet, ethyl violet, oil blue #603, Victoria Pure Blue BOH, malachitegreen, diamond green, phthalocyanine pigments, azo pigments, carbonblack, titanium oxide, brilliant green dye (C. I. 42020), Victoria PureBlue FGA (Linebrow), Victoria BO (Linebrow) (C. I. 42595), Victoria BlueBO (C. I. 44045) rhodamine 6G (C. I. 45160), Benzophenone compounds suchas 2,4-dihydroxybenzophenone and 2,2′,4,4′-tetrahydroxybenzophenone,salicylic acid compounds such as phenyl salicylate and 4-t-butylphenylsalicylate, phenylacrylate compounds such asethyl-2-cyano-3,3-diphenylacrylate, and2′-ethylhexyl-2-cyano-3,3-diphenylacrylate, benzotriazole compounds suchas 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, and2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole,coumarin compounds such as 4-methyl-7-diethylamino-1-benzopyran-2-one,thioxanthone compounds such as diethylthioxanthone, stilbene compounds,naphthalic acid compounds, azo dyes, Phthalocyanine blue, phthalocyaninegreen, iodine green, Victoria blue, naphthalene black, Photopia methylviolet, bromphenol blue and bromcresol green, laser dyes such asRhodamine G6, Coumarin 500, DCM(4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H pyran)),Kiton Red 620, Pyrromethene 580, or the like. Additionally, one or morecoloring agents may be used in combination to provide the desiredcoloring.

Adhesion additives may also be added to the photoresist 111 in order topromote adhesion between the photoresist 111 and an underlying layerupon which the photoresist 111 has been applied (e.g., the layer to bepatterned 109). In an embodiment the adhesion additives include a silanecompound with at least one reactive substituent such as a carboxylgroup, a methacryloyl group, an isocyanate group and/or an epoxy group.Specific examples of the adhesion components include trimethoxysilylbenzoic acid, γ-methacryloxypropyl trimethoxy silane,vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxy silane, γ-glycidoxypropyl trimethoxy silane,β-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, benzimidazoles andpolybenzimidazoles, a lower hydroxyalkyl substituted pyridinederivative, a nitrogen heterocyclic compound, urea, thiourea,8-oxyquinoline, 4-hydroxypteridine and derivatives, 1,10-phenanthrolineand derivatives, 2,2′-bipyridine and derivatives, benzotriazoles;organophosphorus compounds, phenylenediamine compounds,2-amino-1-phenylethanol, N-phenylethanolamine, N-ethyldiethanolamine,N-ethylethanolamine and derivatives, benzothiazole, and abenzothiazoleamine salt having a cyclohexyl ring and a morpholine ring,3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane,3-methacryloyloxypropyltrimethoxysilane, vinyl trimethoxysilane,combinations of these, or the like.

Surface leveling agents may additionally be added to the photoresist 111in order to assist a top surface of the photoresist 111 to be level sothat impinging light will not be adversely modified by an unlevelsurface. In an embodiment surface leveling agents may includefluoroaliphatic esters, hydroxyl terminated fluorinated polyethers,fluorinated ethylene glycol polymers, silicones, acrylic polymerleveling agents, combinations of these, or the like.

In an embodiment the polymer resin and the PACs, along with any desiredadditives or other agents, are added to the solvent for application.Once added, the mixture is then mixed in order to achieve an evencomposition throughout the photoresist 111 in order to ensure that thereare no defects caused by an uneven mixing or non-constant composition ofthe photoresist 111. Once mixed together, the photoresist 111 may eitherbe stored prior to its usage or else used immediately.

Once ready, the photoresist 111 may be utilized by initially applyingthe photoresist 111 onto the layer to be patterned 109. The photoresist111 may be applied to the layer to be patterned 109 so that thephotoresist 111 coats an upper exposed surface of the layer to bepatterned 109, and may be applied using a process such as a spin-oncoating process, a dip coating method, an air-knife coating method, acurtain coating method, a wire-bar coating method, a gravure coatingmethod, a lamination method, an extrusion coating method, combinationsof these, or the like. In an embodiment the photoresist 111 may beapplied such that it has a thickness over the surface of the layer to bepatterned 109 of between about 10 nm and about 300 nm, such as about 150nm.

Once the photoresist 111 has been applied to the semiconductorsubstrate, a pre-bake of the photoresist 111 is performed in order tocure and dry the photoresist 111 prior to exposure to finish theapplication of the photoresist 111. The curing and drying of thephotoresist 111 removes the solvent component while leaving behind thepolymer resin, the PACs, cross-linking agents, and the other chosenadditives. In an embodiment the pre-bake may be performed at atemperature suitable to evaporate the solvent, such as between about 40°C. and 150° C., although the precise temperature depends upon thematerials chosen for the photoresist 111. The pre-bake is performed fora time sufficient to cure and dry the photoresist 111, such as betweenabout 10 seconds to about 5 minutes, such as about 90 seconds.

FIG. 2 illustrates an exposure of the photoresist 111 to form an exposedregion 201 and an unexposed region 203 within the photoresist 111. In anembodiment the exposure may be initiated by placing the semiconductordevice 100 and the photoresist 111, once cured and dried, into animaging device 200 for exposure. The imaging device 200 may comprise asupport plate 205, an energy source 207, a patterned mask 209 betweenthe support plate 205 and the energy source 207, and optics 213. In anembodiment the support plate 205 is a surface to which the semiconductordevice 100 and the photoresist 111 may be placed or attached to andwhich provides support and control to the substrate 101 during exposureof the photoresist 111. Additionally, the support plate 205 may bemovable along one or more axes, as well as providing any desired heatingor cooling to the substrate 101 and photoresist 111 in order to preventtemperature gradients from affecting the exposure process.

In an embodiment the energy source 207 supplies energy 211 such as lightto the photoresist 111 in order to induce a reaction of the PACs, whichin turn reacts with the polymer resin to chemically alter those portionsof the photoresist 111 to which the energy 211 impinges. In anembodiment the energy 211 may be electromagnetic radiation, such asg-rays (with a wavelength of about 436 nm), i-rays (with a wavelength ofabout 365 nm), ultraviolet radiation, far ultraviolet radiation, x-rays,electron beams, or the like. The energy source 207 may be a source ofthe electromagnetic radiation, and may be a KrF excimer laser light(with a wavelength of 248 nm), an ArF excimer laser light (with awavelength of 193 nm), a F₂ excimer laser light (with a wavelength of157 nm), or the like, although any other suitable source of energy 211,such as mercury vapor lamps, xenon lamps, carbon arc lamps or the like,may alternatively be utilized.

The patterned mask 209 is located between the energy source 207 and thephotoresist 111 in order to block portions of the energy 211 to form apatterned energy 215 prior to the energy 211 actually impinging upon thephotoresist 111. In an embodiment the patterned mask 209 may comprise aseries of layers (e.g., substrate, absorbance layers, anti-reflectivecoating layers, shielding layers, etc.) to reflect, absorb, or otherwiseblock portions of the energy 211 from reaching those portions of thephotoresist 111 which are not desired to be illuminated. The desiredpattern may be formed in the patterned mask 209 by forming openingsthrough the patterned mask 209 in the desired shape of illumination.

Optics (represented in FIG. 2 by the trapezoid labeled 213) may be usedto concentrate, expand, reflect, or otherwise control the energy 211 asit leaves the energy source 207, is patterned by the patterned mask 209,and is directed towards the photoresist 111. In an embodiment the optics213 comprise one or more lenses, mirrors, filters, combinations ofthese, or the like to control the energy 211 along its path.Additionally, while the optics 213 are illustrated in FIG. 2 as beingbetween the patterned mask 209 and the photoresist 111, elements of theoptics 213 (e.g., individual lenses, mirrors, etc.) may also be locatedat any location between the energy source 207 (where the energy 211 isgenerated) and the photoresist 111.

In an embodiment the semiconductor device 100 with the photoresist 111is placed on the support plate 205. Once the pattern has been aligned tothe semiconductor device 100, the energy source 207 generates thedesired energy 211 (e.g., light) which passes through the patterned mask209 and the optics 213 on its way to the photoresist 111. The patternedenergy 215 impinging upon portions of the photoresist 111 induces areaction of the PACs within the photoresist 111. The chemical reactionproducts of the PACs' absorption of the patterned energy 215 (e.g.,acids/bases/free radicals) then reacts with the polymer resin,chemically altering the photoresist 111 in those portions that wereilluminated through the patterned mask 209.

In a specific example in which the patterned energy 215 is a 193 nmwavelength of light, the PAC is a photoacid generator, and the group tobe decomposed is a carboxylic acid group on the hydrocarbon structureand a cross linking agent is used, the patterned energy 215 will impingeupon the photoacid generator and the photoacid generator will absorb theimpinging patterned energy 215. This absorption initiates the photoacidgenerator to generate a proton (e.g., a H+ ion) within the photoresist111. When the proton impacts the carboxylic acid group on thehydrocarbon structure, the proton will react with the carboxylic acidgroup, chemically altering the carboxylic acid group and altering theproperties of the polymer resin in general. The carboxylic acid groupwill then react with the cross-linking agent to cross-link with otherpolymer resins within the photoresist 111.

Optionally, the exposure of the photoresist 111 may occur using animmersion lithography technique. In such a technique an immersion medium(not individually illustrated in FIG. 2) may be placed between theimaging device 200 (and particularly between a final lens of the optics213) and the photoresist 111. With this immersion medium in place, thephotoresist 111 may be patterned with the patterned energy 215 passingthrough the immersion medium.

In this embodiment a protective layer (also not individually illustratedin FIG. 2) may be formed over the photoresist 111 in order to preventthe immersion medium from coming into direct contact with thephotoresist 111 and leaching or otherwise adversely affecting thephotoresist 111. In an embodiment the protective layer is insolublewithin the immersion medium such that the immersion medium will notdissolve it and is immiscible in the photoresist 111 such that theprotective layer will not adversely affect the photoresist 111.Additionally, the protective layer is transparent so that the patternedenergy 215 may pass through the protective layer.

In an embodiment the protective layer comprises a protective layer resinwithin a protective layer solvent. The material used for the protectivelayer solvent is, at least in part, dependent upon the components chosenfor the photoresist 111, as the protective layer solvent should notdissolve the materials of the photoresist 111 so as to avoid degradationof the photoresist 111 during application and use of the protectivelayer. In an embodiment the protective layer solvent includes alcoholsolvents, fluorinated solvents, and hydrocarbon solvents.

Specific examples of materials that may be utilized for the protectivelayer solvent include methanol, ethanol, 1-propanol, isopropanol,n-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol,3-methyl-1-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol,2-pentanol, 3-pentanol, n-hexanol, cyclohecanol, 1-hexanol, 1-heptanol,1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol,3-octanol, 4-octanol, 2-methyl-2-butanol, 3-methyl-1-butanol,3-methyl-2-butanol, 2-methyl-1-butanol, 2-methyl-1-pentanol,2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol,3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol,4-methyl-2-pentanol, 2,2,3,3,4,4-hexafluoro-1-butanol,2,2,3,3,4,4,5,5-octafluoro-1-pentanol,2,2,3,3,4,4,5,5,6,6-decafluoro-1-hexanol,2,2,3,3,4,4-hexafluoro-1,5-pentanediol,2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol,2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-diol, 2-fluoroanisole,2,3-difluoroanisole, perfluorohexane, perfluoroheptane,perfluoro-2-pentanone, perfluoro-2-butyltetrahydrofuran,perfluorotetrahydrofuran, perfluorotributylamine,perfluorotetrapentylamine, toluene, xylene and anisole, and aliphatichydrocarbon solvents, such as n-heptane, n-nonane, n-octane, n-decane,2-methylheptane, 3-methylheptane, 3,3-dimethylhexane,2,3,4-trimethylpentane, combinations of these, or the like.

The protective layer resin may comprise a protective layer repeatingunit. In an embodiment the protective layer repeating unit may be anacrylic resin with a repeating hydrocarbon structure having a carboxylgroup, an alicyclic structure, an alkyl group having one to five carbonatoms, a phenol group, or a fluorine atom-containing group. Specificexamples of the alicyclic structure include a cyclohexyl group, anadamantyl group, a norbornyl group, a isobornyl group, a tricyclodecylgroup, a tetracyclododecyl group, and the like. Specific examples of thealkyl group include an n-butyl group, an isobutyl group, or the like.However, any suitable protective layer resin may alternatively beutilized.

The protective layer composition may also include additional additivesto assist in such things as adhesion, surface leveling, coating, and thelike. For example, the protective layer composition may further comprisea protective layer surfactant, although other additives may also beadded, and all such additions are fully intended to be included withinthe scope of the embodiment. In an embodiment the protective layersurfactant may be a alkyl cationic surfactant, an amide-type quaternarycationic surfactant, an ester-type quaternary cationic surfactant, anamine oxide surfactant, a betaine surfactant, an alkoxylate surfactant,a fatty acid ester surfactant, an amide surfactant, an alcoholsurfactant, an ethylenediamine surfactant, or a fluorine- and/orsilicon-containing surfactant.

Specific examples of materials that may be used for the protective layersurfactant include polyoxyethylene alkyl ethers, such as polyoxyethylenelauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl etherand polyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers, suchas polyoxyethylene octyl phenol ether and polyoxyethylene nonyl phenolether; polyoxyethylene-polyooxypropylene block copolymers; sorbitanfatty acid esters, such as sorbitan monolaurate, sorbitan monopalmitate,sorbitan monostearate, sorbitan monooleate, sorbitan trioleate andsorbitan tristearate; and polyoxyethylene sorbitan monolaurate,polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitanmonostearate, polyoxyethylene sorbitan trioleate and polyoxyethylenesorbitan tristearate.

Prior to application of the protective layer onto the photoresist 111,the protective layer resin and desired additives are first added to theprotective layer solvent to form a protective layer composition. Theprotective layer solvent is then mixed to ensure that the protectivelayer composition has a consistent concentration throughout theprotective layer composition.

Once the protective layer composition is ready for application, theprotective layer composition may be applied over the photoresist 111. Inan embodiment the application may be performed using a process such as aspin-on coating process, a dip coating method, an air-knife coatingmethod, a curtain coating method, a wire-bar coating method, a gravurecoating method, a lamination method, an extrusion coating method,combinations of these, or the like. In an embodiment the photoresist 111may be applied such that it has a thickness over the surface of thephotoresist 111 of about 100 nm.

After the protective layer composition has been applied to thephotoresist 111, a protective layer pre-bake may be performed in orderto remove the protective layer solvent. In an embodiment the protectivelayer pre-bake may be performed at a temperature suitable to evaporatethe protective layer solvent, such as between about 40° C. and 150° C.,although the precise temperature depends upon the materials chosen forthe protective layer composition. The protective layer pre-bake isperformed for a time sufficient to cure and dry the protective layercomposition, such as between about 10 seconds to about 5 minutes, suchas about 90 seconds.

Once the protective layer has been placed over the photoresist 111, thesemiconductor device 100 with the photoresist 111 and the protectivelayer are placed on the support plate 205, and the immersion medium maybe placed between the protective layer and the optics 213. In anembodiment the immersion medium is a liquid having a refractive indexgreater than that of the surrounding atmosphere, such as having arefractive index greater than 1. Examples of the immersion medium mayinclude water, oil, glycerine, glycerol, cycloalkanols, or the like,although any suitable medium may alternatively be utilized.

The placement of the immersion medium between the protective layer andthe optics 213 may be done using, e.g., an air knife method, wherebyfresh immersion medium is applied to a region between the protectivelayer and the optics 213 and controlled using pressurized gas directedtowards the protective layer to form a barrier and keep the immersionmedium from spreading. In this embodiment the immersion medium may beapplied, used, and removed from the protective layer for recycling sothat there is fresh immersion medium used for the actual imagingprocess.

However, the air knife method described above is not the only method bywhich the photoresist 111 may be exposed using an immersion method. Anyother suitable method for imaging the photoresist 111 using an immersionmedium, such as immersing the entire substrate 101 along with thephotoresist 111 and the protective layer, using solid barriers insteadof gaseous barriers, or using an immersion medium without a protectivelayer, may also be utilized. Any suitable method for exposing thephotoresist 111 through the immersion medium may be used, and all suchmethods are fully intended to be included within the scope of theembodiments.

For example, in a particular embodiment in which the PAC is a photoacidgenerator and the group which will decompose is an acid labile group,the impinging patterned energy 215 will initiate the photoacidgenerators to generate, e.g., a acid in the form of a hydrogen proton(H⁺). The hydrogen atoms generated will then react with the acid labilegroup in the polymer resin, removing portions or all of the acid labilegroup, and modifying the chemical structure of the reacted polymerresin, leading to a change in the solubility of the polymer resin. Inembodiments in which the cross-linking agent is used, the generatedacids will also initiate the cross-linking agents to react with thepolymer resins, cross-linking the polymer resins to each other andincreasing the molecular weight of the resulting polymer.

After the photoresist 111 has been exposed to the patterned energy 215,a post-exposure baking may be used in order to assist in the generating,dispersing, and reacting of the acid/base/free radical generated fromthe impingement of the patterned energy 215 upon the PACs during theexposure. Such assistance helps to create or enhance chemical reactionswhich generate chemical differences between the exposed region 201 andthe unexposed region 203 within the photoresist 111. These chemicaldifferences also caused differences in the solubility between theexposed region 201 and the unexposed region 203. In an embodiment thispost-exposure baking may occur at temperatures of between about 50° C.and about 160° C. for a period of between about 40 seconds and about 120seconds.

FIGS. 3A-3B illustrate a development of the photoresist 111 with the useof a developer 301 after the photoresist 111 has been exposed. After thephotoresist 111 has been exposed and the post-exposure baking hasoccurred, the photoresist 111 may be developed using either a positivetone developer or a negative tone developer, depending upon the desiredpattern for the photoresist 111. In an embodiment in which the exposedregion 201 of the photoresist 111 is desired to be removed to form apositive tone, a positive tone developer such as a basic aqueoussolution may be utilized to remove those portions of the photoresist 111which were exposed to the patterned energy 215 and which have had theirsolubility modified and changed through the chemical reactions. Suchbasic aqueous solutions may include tetra methyl ammonium hydroxide(TMAH), tetra butyl ammonium hydroxide, sodium hydroxide, potassiumhydroxide, sodium carbonate, sodium bicarbonate, sodium silicate, sodiummetasilicate, aqueous ammonia, monomethylamine, dimethylamine,trimethylamine, monoethylamine, diethylamine, triethylamine,monoisopropylamine, diisopropylamine, triisopropylamine, monobutylamine,dibutylamine, monoethanolamine, diethanolamine, triethanolamine,dimethylaminoethanol, diethylaminoethanol, potassium metasilicate,sodium carbonate, tetraethylammonium hydroxide, combinations of these,or the like.

If a negative tone development is desired, an organic solvent orcritical fluid may be utilized to remove those portions of thephotoresist 111 which were not exposed to the energy and, as such,retain their original solubility. Specific examples of materials thatmay be utilized include hydrocarbon solvents, alcohol solvents, ethersolvents, ester solvents, critical fluids, combinations of these, or thelike. Specific examples of materials that can be used for the negativetone solvent include hexane, heptane, octane, toluene, xylene,dichloromethane, chloroform, carbon tetrachloride, trichloroethylene,methanol, ethanol, propanol, butanol, critical carbon dioxide, diethylether, dipropyl ether, dibutyl ether, ethyl vinyl ether, dioxane,propylene oxide, tetrahydrofuran, cellosolve, methyl cellosolve, butylcellosolve, methyl carbitol, diethylene glycol monoethyl ether, acetone,methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone,methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pyridine,formamide, N,N-dimethyl formamide, or the like.

However, as one of ordinary skill in the art will recognize, the abovedescription of positive tone developers and negative tone developers areonly intended to be illustrative and are not intended to limit theembodiments to only the developers listed above. Rather, any suitabletype of developer, including acid developers or even water developers,that may be utilized to selectively remove a portion of the photoresist111 that has a different property (e.g., solubility) than anotherportion of the photoresist 111, may alternatively be utilized, and allsuch developers are fully intended to be included within the scope ofthe embodiments.

In an embodiment in which immersion lithography is utilized to exposethe photoresist 111 and a protective layer is utilized to protect thephotoresist 111 from the immersion medium, the developer 301 may bechosen to remove not only those portions of the photoresist 111 that aredesired to be removed, but may also be chosen to remove the protectivelayer in the same development step. Alternatively, the protective layermay be removed in a separate process, such as by a separate solvent fromthe developer 301 or even an etching process to remove the protectivelayer from the photoresist 111 prior to development.

FIG. 3A illustrates an application of the developer 301 to thephotoresist 111 using, e.g., a spin-on process. In this process thedeveloper 301 is applied to the photoresist 111 from above thephotoresist 111 while the semiconductor device 100 (and the photoresist111) is rotated. In an embodiment the developer 301 may be supplied at aflow rate of between about 10 ml/min and about 2000 ml/min, such asabout 1000 ml/min, while the semiconductor device 100 is being rotatedat a speed of between about 100 rpm and about 3500 rpm, such as about1500 rpm. In an embodiment the developer 301 may be at a temperature ofbetween about 10° C. and about 80° C., such as about 50° C., and thedevelopment may continue for between about 1 minute to about 60 minutes,such as about 30 minutes.

However, while the spin-on method described herein is one suitablemethod for developing the photoresist 111 after exposure, it is intendedto be illustrative and is not intended to limit the embodiments. Rather,any suitable method for development, including dip processes, puddleprocesses, spray-on processes, combinations of these, or the like, mayalternatively be used. All such development processes are fully intendedto be included within the scope of the embodiments.

FIG. 3B illustrates a cross-section of the development process in whicha positive tone developer is utilized. As illustrated, the developer 301is applied to the photoresist 111 and dissolves the exposed portion 201of the photoresist 111. This dissolving and removing of the exposedportion 201 of the photoresist 111 leaves behind an opening within thephotoresist 111 that patterns the photoresist 111 in the shape of thepatterned energy 215, thereby transferring the pattern of the patternedmask 209 to the photoresist 111.

FIGS. 4A and 4B illustrate the photoresist 111 after the developer hasbeen removed, with FIG. 4B illustrating a close-up, expanded view thatillustrates a portion of the atoms (not drawn to scale) along thevarious surfaces within the dashed region 400 in FIG. 4A. In anembodiment in which a spin-on process is utilized, the developer 301 maybe removed by stopping the flow of developer 301 to the photoresist 111and allowing the photoresist 111 to spin-dry, although any suitablemethod to remove the developer 301 may alternatively be utilized.

However, while the removal of the developer 301 also removes any of thephotoresist 111 that had been absorbed by the developer 301, a residue401 may be left behind on the photoresist 111. This residue 401 may bethe result of side products, unreacted groups, or unfinished reactionsbetween the PACs, the polymer resin, and/or the cross-linking agentwithin the photoresist 111. This residue 401, if left untreated suchthat it remains on the surface of the photoresist 111, will interferewith further processing of the semiconductor device 100, leading to anincrease in defects during processing and an overall decrease in yield.

FIG. 4B illustrates a closer view of the residue 401, which may compriseone or more of the hydrocarbon structures of the polymer resin.Remaining on the hydrocarbon structure is one or more unreacted groups(represented in FIG. 4B by the square labeled 402) that were supposed todecompose but that remain unreacted. This may have occurred because thegroups which will decompose on the repeating units (described above withrespect to FIG. 1) did not react with the acid/base/free radical thatwas generated by the PACs, causing hydrophobic acid leaving groups(e.g., cycloalkane or adamantine) to remain and cause the hydrocarbonstructure to be insoluble in the developer.

Alternatively, in some cases the groups which will decompose maypartially but not fully react with the acid/base/free radical generatedby the PACs, causing an incomplete reaction that leaves behind apartially reacted group (represented in FIG. 4B by the triangle labeled404), such as a hydrophilic de-protected acid leaving group. Suchincomplete reactions can cause the residue 401 to become onlysemi-soluble in the developer 301 or else remain completely insoluble inthe developer 301, thereby affecting the ability of the developer 301 toremove the polymer resin, resulting in the residue 401. In a particularembodiment in which the acid leaving group comprises a carboxyl group405 incorporated into the structure prior to exposure, a reaction withthe acid/base/free radical may remove a portion of the structure but notremove the carboxyl group 405, which will remain bonded to the polymerresin in the residue 401.

Given these unreacted or incompletely reacted groups that remain on theresidue 401, the residue 401 easily redoposits on the photoresist 111,where the presence of the residue 401 may interfere with the furtherprocessing of the semiconductor device 100. Additionally, given thegroups that may be left on the residue (e.g., the OH group in thecarboxylic group) and the groups that may be present on the surface ofthe photoresist 111 (e.g., the OH group on the photoresist 111), thereis also hydrogen bonding (represented by the arrow in FIG. 4B labeled403) that occurs between the residue 401 and the surface of thephotoresist 111. This hydrogen bonding 403 impedes the removal of theresidue 401 using cleaning processes. As such, neutral or acidic waterwashing used as a way of removing and cleaning the photoresist 111 afterdevelopment is insufficient to remove the residue 401 that may haveformed and which will continue to cause defects during furtherprocessing.

As such, FIGS. 5A-5C illustrate the beginning of a cleaning process thatwill aid in the removal of the residue 401, with FIG. 5A illustrating anapplication of cleaning materials 502, FIG. 5B illustrating across-section view of a start of the cleaning process, and FIG. 5Cillustrating a close-up view of representative atoms along the residue401 and the surface of the photoresist 111. In an embodiment thecleaning materials 502 may be chosen in order to provide an alkalineenvironment 500 for the cleaning process and may, for example, comprisea neutral solvent 501 along with an alkaline chemical 503 in order togenerate and maintain the alkaline environment 500.

In an embodiment the neutral solvent 501 may be water, such asde-ionized water that may be utilized for removing any left-overdeveloper 301 or residue 401 from the surface of the photoresist 111.The de-ionized water may optionally include carbon dioxide dissolvedinto the de-ionized water. However, any suitable neutral solvent 501 mayalternatively be utilized. In an embodiment the neutral solvent may beapplied to the photoresist 111 using, e.g., a spin-coating method at aflow rate between about 100 ml/min to about 2000 ml/min.

Additionally, in order to form the alkaline environment 500, thealkaline chemical 503 is also applied to the photoresist 111 along withthe neutral solvent 501 in order to raise the pH of the neutral solvent501 and form the alkaline environment 500. In an embodiment the alkalinechemical 503 is any chemical that may be used to adjust the pH of theneutral solvent 501 upwards from neutral. In an embodiment in which thedeveloper 301 used to develop the photoresist 111 is an alkalinedeveloper, the developer 301 used to develop the photoresist 111 may beused as the alkaline chemical 503, although any other alkaline chemical,such as guanidinium, sodium hydroxide, calcium hydroxide, combinationsof these, or the like may alternatively be used. The alkaline chemical503 may be applied to the photoresist 111 at the same time as theneutral solvent 501 and at a flow rate, e.g., of between about 10 ml/minto about 2000 ml/min.

The relative flow rates of the neutral solvent 501 to the alkalinechemical 503 may be modified in order to provide the desired alkalinityfor the alkaline environment 500. In an embodiment the alkalineenvironment 500 may be held to have a pH range of greater than 7 andless than about 12. For example, in an embodiment in which the neutralsolvent is deionized water and the alkaline chemical is the alkalinedeveloper TMAH 2.38%, to achieve a desired pH of 10, the flow rate ofthe neutral solvent 501 may be 100 ml/min˜2000 ml/min while the flowrate of the alkaline chemical 503 may be 10 ml/min˜2000 ml/min.

Additionally, while the neutral solvent 501 and the alkaline chemical503 are illustrated in FIG. 5A as being dispersed onto the photoresist111 separately, this is merely one example of the way the neutralsolvent 501 and the alkaline chemical 503 may be applied. Alternatively,the neutral solvent 501 and the alkaline chemical 503 may be pre-mixedinto a single solution (not illustrated) and the single solution maythen be applied to the photoresist 111, or else the neutral solvent 501and the alkaline chemical 503 may be mixed in-line right before theirapplication onto the photoresist 111. Any suitable method of forming thealkaline environment 500 on the photoresist 111 may alternatively beused, and all such methods are fully intended to be included within thescope of the embodiments.

FIG. 5B illustrates a cross-sectional view of the alkaline environment500 present on the surface of the photoresist 111 and on the surface ofthe residue 401. As illustrated, the alkaline environment 500 covers thesurface of the photoresist 111 and the residue 401, thereby encompassingboth the surface of the photoresist 111 and the surfaces of the residue401 and able to interact with the atoms present on both the surface ofthe photoresist 111 and the surface of the residue 401.

FIG. 5C illustrates a close-up, expanded view of the surfaces of thephotoresist 111 and the residue 401, and also illustrates representativeatoms along each of the surfaces while the surfaces are within thealkaline environment 500. For example, the surface of the photoresist111, instead of being terminated with OH groups as described above inFIG. 4B, has been modified by the alkaline environment 500 to remove thehydrogen atom and leave the surface of the photoresist 111 terminatedwith an O⁻ atom. Similarly, any leftover OH groups that may be presentalong the residue 401 (e.g., the OH group located on the carboxylicgroup 405 of the partially reacted group 404) may be modified byremoving the hydrogen atom and terminating the surface of the residue401 with an O⁻ atom.

By modifying the terminating groups on both the surface of thephotoresist 111 as well as groups located along the surface of theresidue 401, both the surface of the photoresist 111 and the surface ofthe residue 401 will have groups with negative charges. In theparticular embodiment described above in which the photoresist 111initially has a surface of OH groups and the residue 401 has carboxylicacids groups, both the surface of the photoresist 111 and the surface ofthe residue 401 in the alkaline environment 500 will have O⁻ groups. Assuch, the original hydrogen bonding 403 (see FIG. 4) that attracted theresidue 401 to the surface of the photoresist 111 and made it moredifficult to remove the residue 401 is removed.

Additionally, given that both the surface of the photoresist 111 and thesurface of the residue 401 have a negative charge, the negative chargesalong both surfaces will repulse the other surface, causing a repulsiveCoulomb force (represented in FIG. 5C by the arrow labeled 507) betweenthe residue 401 and the photoresist 111. This repulsive force 507,instead of making it harder to remove the residue 401, will actuallyassist in the removal of the residue 401 from the surface of thephotoresist 111 as well as de-charge the positive charging particle fromits low resistance of solution. As such, the cleaning of the residue 401from the photoresist 111 is more easily performed, leading to an overallcleaner photoresist 111, which will lead to fewer processing defects anda larger overall yield.

However, adding the alkaline chemical 503 to the neutral solvent 501 isnot the only method by which the residue 401 and the surface of thephotoresist 111 may be placed into the alkaline environment 500. Inanother embodiment the alkaline environment 500 may be created using aStandard Clean (SC)-1 cleaning process to remove the residue 401 andmaintain the alkaline environment 500. In an embodiment in which theSC-1 cleaning process is used, the photoresist 111 is exposed to asolution of ammonium hydroxide (NH₄OH), hydrogen peroxide (H₂O₂), andwater in a suitable ratio to maintain the alkaline environment 500 to adesired pH level. In a particular embodiment the ratio may be a 1:1:5ratio, although any suitable ratio may alternatively be utilized, andthe ratios may be tuned to the desired pH level.

The cleaning solution of the SC-1 cleaning process may be applied to thephotoresist 111 and the residue 401 using, e.g., a spin-on methodwhereby the cleaning solution of the SC-1 cleaning process is dispensedonto the photoresist 111 at a flow rate of between about 10 ml/min andabout 2000 ml/min, such as about 1000 ml/min, while the substrate 101and the photoresist 111 are spun at a speed of between about 500 rpm andabout 3000 rpm, such as about 1500 rpm. However, any suitable method ofapplying the cleaning solution of the SC-1 cleaning process, such as adip method or a spray-on method, may alternatively be utilized, and allsuch methods are fully intended to be included within the scope of theembodiments.

When the cleaning solution of the SC-1 cleaning process comes intocontact with the photoresist 111 and the residue 401, the alkalineenvironment 500 of the cleaning solution of the SC-1 cleaning processwill react with the groups in a similar fashion as described above withrespect to the embodiment using an alkaline developer. In particular,the alkaline environment 500 will react such that the surface of thephotoresist 111 and the surface of the residue 401 have O⁻ groups whichgenerate the repulsive force 507 and repel the residue 401 from thesurface of the photoresist 111. As such, the alkaline environment 500assists in the removal of the residue 401, helping to decrease defectsand increase the overall yield of the manufacturing process.

Furthermore, while two embodiments of the alkaline environment 500 (amixture of the alkaline developer and deionized water and an SC-1cleaning process) have been described in detail above, one of ordinaryskill in the art will recognize that these two embodiments are intendedas being illustrative and the alkaline environment 500 is not intendedto be limited to these two embodiments. Rather, any suitable alkalineenvironment that can help to modify the surface of the photoresist 111and/or the surface of the residue 401 to assist in the removal of theresidue may alternatively be utilized, and all such alkalineenvironments are fully intended to be included within the scope of theembodiments.

Additionally, a cleaning surfactant may be utilized along with thecleaning materials 502 or the SC-1 cleaning solution to create thealkaline environment 500. In an embodiment the cleaning surfactant hashydrophobic groups which, once the cleaning surfactant penetrates to thesurface of the residue 401, will adhere to and interfere with thehydrophobic groups of the polymer resin and its remaining groups withinthe residue 401. This interference from the cleaning surfactant helps tomake the residue 401 easier to dissolve in the cleaning materials 502 orthe SC-1 cleaning solution. In an embodiment the cleaning surfactant mayhave the following structure:

where, n may be from between 1 to 15 and the R₁ and R₂ groups may be analkyl group hydrogen attached to the hydrocarbon with a carbon numberbetween 1 and 10. The alkyl group may be either straight, branched, orhave a cyclic structure, and may be single, double, or triple bondedalkyl structure. The alkyl group may also comprise hetero atoms such asnitrogen, oxygen, or fluorine. R₁ and R₂ may also comprise a nitro- or asulfonic-group.

In an embodiment in which the cleaning materials 502 are dispensed ontothe photoresist 111 individually, the cleaning surfactant may bedispensed at a flow rate of between about 10 ml/min and about 2000ml/min, such as about 300 ml/min. However, in an embodiment in which thecleaning materials 502 are pre-mixed (either in-line or in a batchprocess), the cleaning surfactant may have a concentration within thecleaning solution of between about 0.001 wt % and about 40 wt %, such asabout 0.1 wt %.

Other additives may also be mixed in with the cleaning materials 502 orthe SC-1 cleaning solution. For example, a cleaning additive may beadded to protect the photoresist 111 as well as to protect the cleaningsurfactant. In an embodiment the cleaning additive is used to chemicallyreact with the hydrophilic structure of the photoresist 111 in order toterminate the photoresist 111 with a hydrophobic termination, therebymaking dissolution of the photoresist 111 harder. In an embodiment thecleaning additive may have the following structure:

where the R₁, R₂, and R₃ groups may contain alkyl functional structureswith straight, branched, or cyclic structures, and may be single, doubleor tripled bonded structures. The alkyl functional structure maycomprise hydrogen, and may be a hydrocarbon chain with from one to tencarbons. At least one of the R₁, R₂, and R₃ groups may comprise an aminestructure. The R₁, R₂, and R₃ groups may also comprise at least onesubstituted nitrogen, oxygen, or fluorine atom. Additionally, the R₁,R₂, and R₃ groups may also contain nitro- or sulfonic-groups.

In an embodiment in which the cleaning materials 502 are dispensed ontothe photoresist 111 individually, the cleaning additive may be dispensedat a flow rate of between about 10 ml/min and about 2000 ml/min, such asabout 200 ml/min. However, in an embodiment in which the cleaningmaterials 502 are pre-mixed (either in-line or in a batch process), thecleaning additive may have a concentration within the cleaning solutionof between about 0.001 wt % and about 40 wt %, such as about 0.1 wt %.

FIGS. 6A and 6B illustrate reductions in defect counts that can beobtained by utilizing the alkaline environment 500 to clean the residue401 off of the photoresist 111. The test method charted in FIG. 6A,which illustrates a defect comparison test, illustrates a 95% reductionin the defect count from a cleaning performed in a non-alkalineenvironment to a cleaning performed in an alkaline environment.Similarly, in the test method charted in FIG. 6B, which illustrates adefect comparison test, a 90% reduction in defect counts can berealized. As such, using an alkaline environment 500 to clean thephotoresist 111 after development can lead to fewer defects and anoverall greater yield for the manufacturing process.

After the residue 401 has been removed from the surface of thephotoresist 111, additional processing may be performed on thephotoresist 111 to prepare it for use. In an embodiment one such processmay be a Finishing-up by Improved Rinse Materials (FIRM) treatment thathelps to reduce any pattern collapse that may occur in the photoresist111. In an embodiment the FIRM treatment rinses the photoresist 111 witha mixture of deionized water and surfactants in order to reduce thesurface tension of the rinse during, e.g., a spin dry process, therebyreducing the stressed generated by the rinsing materials during the spindrying process.

In an embodiment the surfactants mixed with the deionized water may besurfactants such as alkyl carboxylates, pentaethylene glycol, orperfluorooctanesulfonic acid. The surfactants may be mixed with thedeionized water so that the surfactants have a concentration of betweenabout 0.001 wt % and about 40 wt %, such as about 0.1 wt %, and may beapplied to the photoresist 111 using, e.g., a spin-on process whereinthe mixture is flowed onto the photoresist 111 at a flow rate of betweenabout 10 ml/min and about 2000 ml/min, such as about 300 ml/min, whilethe photoresist 111 is rotated at a speed of between about 500 rpm andabout 3000 rpm, such as about 1500 rpm. Once the FIRM treatment iscompleted, the photoresist 111 may be dried using, e.g., a spin dryingprocess.

Once the photoresist 111 is rinsed and dried, further processing may beperformed on the layer to be patterned 109 while the photoresist 111 isin place. As one example, a reactive ion etch or other etching processmay be utilized, to transfer the pattern of the photoresist 111 to theunderlying layer to be patterned 109. Alternatively, in an embodiment inwhich the layer to be patterned 109 is a seed layer, the layer to bepatterned 109 may be plated in order to form, e.g., a copper pillar, orother conductive structure in the opening of the photoresist 111. Anysuitable processing, whether additive or subtractive, that may beperformed while the photoresist 111 is in place may be performed, andall such additional processing are fully intended to be included withinthe scope of the embodiments.

In accordance with an embodiment, a method of manufacturing asemiconductor device comprises developing a photoresist over a substrateand cleaning the photoresist after the developing, the cleaning thephotoresist comprising applying an alkaline environment to a surface ofthe photoresist.

In accordance with another embodiment, a method of manufacturing asemiconductor device comprising removing a developer from a photoresist,the removing the developer leaving behind a residue, is provided. Theresidue is removed from the photoresist, the removing the residuefurther comprising treating a surface of the residue to have a firstcharge and treating a surface of the photoresist to have the firstcharge.

In accordance with yet another embodiment, a method of manufacturing asemiconductor device comprising applying a photoresist to a substrateand developing the photoresist to form a patterned photoresist isprovided. The patterned photoresist is cleaned using an alkalineenvironment, wherein the alkaline environment chemically modifies a topsurface of the photoresist.

Although the present embodiments and their advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the disclosure as defined by the appendedclaims. For example, the precise chemicals utilized in the alkalineenvironment may be modified as suitable to maintain the alkalineenvironment, while the precise processes (such as method of dispensing)may be changed without departing from the scope of the embodiments.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: developing a photoresist over a substrate;cleaning the photoresist after the developing, the cleaning thephotoresist comprising applying an alkaline environment to a surface ofthe photoresist to modify the surface of the photoresist to have a firstcharge and to modify a surface of residue to have the first charge; andafter the cleaning the photoresist, rinsing the photoresist with amixture of deionized water and surfactants.
 2. The method of claim 1,wherein the applying the alkaline environment further comprises applyinga neutral solvent and an alkaline developer.
 3. The method of claim 2,wherein developing the photoresist uses the alkaline developer.
 4. Themethod of claim 1, wherein the applying the alkaline environment furthercomprises performing a Standard Clean-1 cleaning process.
 5. The methodof claim 1, wherein the applying the alkaline environment furthercomprises applying a cleaning surfactant.
 6. The method of claim 5,wherein the cleaning surfactant has the structure

where n is between 1 and 15 and wherein the R₁ and R₂ groups are analkyl group with a carbon number between 1 and
 10. 7. The method ofclaim 1, wherein the applying the alkaline environment further comprisesapplying a cleaning additive.
 8. The method of claim 7, wherein thecleaning additive has the structure

where R₁, R₂ and R₃ are alkyl functional structures with straight,branched, or cyclic structures.
 9. A method of manufacturing asemiconductor device, the method comprising: removing a developer from aphotoresist, the removing the developer leaving behind a residue; andremoving the residue from the photoresist, the removing the residuefurther comprising: treating a surface of the residue to have a firstcharge; and treating a surface of the photoresist to have the firstcharge without removing the surface of the photoresist.
 10. The methodof claim 9, wherein the treating the surface of the photoresist furthercomprises applying a cleaning solution with a pH greater than 7 onto thesurface of the photoresist.
 11. The method of claim 10, wherein thecleaning solution comprises an SC-1 cleaning solution.
 12. The method ofclaim 10, wherein the cleaning solution further comprises: a neutralsolvent; and an alkaline component, wherein the developer has a firstcomposition and the alkaline component has the first composition. 13.The method of claim 10, wherein the treating the surface of the residuefurther comprises applying a cleaning surfactant to the surface of theresidue.
 14. The method of claim 10, wherein the treating the surface ofthe residue further comprises applying a cleaning additive to thesurface of the residue.
 15. A method of manufacturing a semiconductordevice, the method comprising: applying a photoresist to a substrate;developing the photoresist to form a patterned photoresist; and cleaningthe patterned photoresist using an alkaline environment, wherein thealkaline environment is applied by applying a neutral solvent and analkaline chemical separately to the patterned photoresist.
 16. Themethod of claim 15, wherein the cleaning the patterned photoresistremoves residue from the photoresist.
 17. The method of claim 16,wherein the cleaning the patterned photoresist chemically modifies asurface of the residue to have a first charge, the top surface of thephotoresist having the first charge.
 18. The method of claim 16, whereinthe residue comprises a carboxylic acid group.
 19. The method of claim15, wherein the alkaline environment further comprises a cleaningsurfactant.
 20. The method of claim 15, wherein the alkaline environmentfurther comprises a cleaning additive.